Improvement in steam-g-enerators



f timi 0% taaa IMPROVEMEN'I' IN STEAM-GENERATORS.

. The Scheule refen'ed to in these Letters Patent and making part of the same.

T0- 'whom it may conceT-n:

Be it known that I, H. G. BRooKs, of New York, m the county and State of New York, have invented certain new and useful Improvements in' the Construction of Locomotive and other Boilers; and I hereby i declare the following to be a full, clear, and exact description of the same, reference being' had to the accompanying drawings, in which- Figure 1 is 'a longitudinal central section of a portion of a boiler, made in accordance with my invention.

Figure 2 is a transversc Vertical section of the same, .on the line A B, fig. 1.

Figure 3 is a view, on an enlargcd scale, of a portion of the boiler.

The first part of my invention relates more especially to looomotive-boilers, and its obj cct is'to effect the removal of the forward flue-shcet in such boilers with greater convenience and economy than has' heretofore been practicable' In order to remove from an ordinary locomotiyeboiler the forward due-Sheet for repairs or any other' purpose, it has been heretoforeanccessary to first remove the rivets, or a portion of them, which 'secure the smoke-box to the cylinder-part of the boilcr, for the reason that these rivets interfere with the finesheet, and prevent its withdrawal, and this operation not only consutnes considerable time, but is both inconveni'ent and expensive.

In order to obviate this ditficulty, I form a fiange or offset, a, outward, at the end of the forward course,

Za, of the cylinder-portion of the boiler, so that whenl the smoke-arch or box, o, is riveted thcreto, the heads of the rivets d, which fasten the smoke-box to the boiler, may entirely clear the periphery of the ,fiue- Sheet e, which is riveted within the forward course b, in the usual manner. Fromthis construction it results that when the fine-Sheet rivets f are removed, the fiue-sheet can at once be withdrawn without trouble or nterfercnce with the fastening-iivets of the smokebox, thus remedying in a simple and effective manner the difiiculty above named.

The second and main portion vof niy invention re- I lates to the construction of locomotive and other boiiers, land its object is to impart to them greater strength and durability, and to prevent, as far as possible, danger of ruptnre, and consequent explosion.

It is well understood that, explosions, of course, cannot occur exccptas the result of rupture, whatever the theory may be as 'to the causes of rupture.

My own experience in this matter has led me to the conclusion that rupture is occasioncd by the abrupt i Unoqual temperaor points where the vibratory movement is abruptly tcrminatcd.

The points of abrupt terminationiof this vibratory inovement in boilers are the laps or seams where two or more sheets meet; the points where, in locomotiveboilers, the braces or attachments to the frame are rivcted or fastened; and, iu general, all points where'therez is a rigid connection between the boiler and other mechanism or devices.

I have found, after careful and repeatcd investigations of many boiler-explosions, that rupturcs generally take place at these points, that is, either directly under the seam orl lap, or atsome other rigid point determined by the construction and service of the boiler, and that the metal commences to separate at the inner surface of the platcs; this latter effect being due, in a measure, to the fact that the metal at the inner surface is compressed, and therefore already partially disintegrated by the bending of the plate.

As, therefore, the abrupt termination of the vibratory movement of the plates at such points is-a frequent cause of rupture, it follows that by gradually.

chccking the vibratory movement, instead of abruptly and suddenly terminating it, the disintegrating forces will be, as it were, diffused and gradually expended, and will not, as in the former instance, have a concentrated action upon any one part of the boiler-plates; and by this means the rupture of the plates Will be as far as possible prevcnted.

To efiect this -rcsult it is necessary that wherever sea-ms or laps' occur in the construction of the boiler, the end, g, of the inside sheet, K, of the lap, (see fig. 3,) which, unlike the end of the outside Sheet, is not required to be chipped and corked, should be prolonged, and chamfered or tapered, from the outside of the rivet-head h, to the extreme edge of said sheet; in other words, it should be extremely thin at the edge, and then gradually increase in thickness as it approaches the rivet, where it may be of the ordinary thickness.

In ordinary boilers, the end, g, of the inner sheet is out square ofi', or nearly so, and has the same thickness as the other parts of the plate. The consequence is that the Vibrations of the outer sheet m are abruptly terminated when they reach the end, g, and the sudden checking of this movement causes the disintegra tion, gradual scparation, and final rupture of the metal in the plate an, along the line of the lap. But by gradually tapering or chamfering the end, g, the movement is but slightly chccked at irst by the thin edge of the sheet K; then, as it progresses, it meets with graduallyincreasing thickness of the bevelled end of the sheet, until it is at last checked and terminated Without injurious effect, the lap offering a yielding resistance only to the vibratory movemcnts, and thus neutralizing their tendcncy to disintegrat-e the metal, and destroying'the fulcrum, over which, in boilers of ordinary construction, the sheet is gradually broken. Where practicable, the thin edge of the inner sheet of the lap may, with good results, instead of being straight, have a cuiw'ed'or uudulating outline.

i By thus forming the lap, the point at which the rupture, if any, will occu'r, is transfeired from the inner surface of the sheet 'm to the outer surface of the sheet K, where it meets'the abrnpt `end of the sheet m; this end beingr necessarily shaped as shown in the drawings, as it requires to be clipped and corked. But this is comparatively of little importance, for the exterior of the boiler may be inspected at all times, and under the best conditions, for the discovery of any flaw or defect in the plates. Bnt the interior of the boiler can only be examined when the boiler is cold, and the plates consequently contract'ed, so that even if there should be a partial rupture along the line of the inner sheet of the lap, a most rigid inspection lwould in many instanees fail to disclose it. f

The same principle should be carried into the construction of all parts of the boiler, and at all points where the boiler attaches to other mechansm or de- Vices which may tendto check ahruptly the vibration vof the plates. For instance, the braces, which, in locomotives, fasten the boiler to the frame, should have their feet, which are attached to the boiler, largely extended in surface, and so made that a point, at or near the centre of tne foot of the braee, shall be' the thickest portion, tapering gradually thence towards all the edges `of the foot, which edges should be as thin as possible, and with a eurved or irregular outline, if desired. i

The object of giving a curved or irregular Outline to the edge of the laps and other palts is to retard as far as possible the rupture of the plate, which can be torn less readily than across a straight edge, for the same reason that a sheet of paper can be dividedwith greater ease by tearing it over a straight edge than over a crooked or irregular edge, as in the latter case there must be a continuous change of direetion in the line of separation. i

As above indieated, the method I have described of oonstructing boilers,' may be applied to boilers used for any and every purpose, 'the essential feature'being that as far as possible there shall be no abrupt termination to the Vibratory movement of the plates of4 which the boiler lmay be composed.

Having now described my invention, and the manner in which the same is or may` be carried into efi'ect,

What I claim, and desire to secure by Letters Patent, is-

1. A boiler, in which the ends of the inner sheets of the laps or seams are prolonged beyond the fastening-rivets, and chamfered or bevelled, in the manner and for the purposes set folth.

2. The offset, fianged ontwardly, in the lnanner described, on the end of the forward course of the cylinder-portion of the| boiler, in combination with the smoke-arch or box, substantially as and for the purposes set forth.

In `testimonywl1ereof, 1 have signed my name .to this speeifieation, before two subscribing witnesses. H. G. VBROOKS.

Witnesses:

M. L. Hlmmm, J No. W. ROMAINE. 

